1. Field of the Invention
The present invention generally relates to a thin film transistor (TFT) and a method of manufacturing the same, and more particularly to an organic thin film transistor (OTFT) and a method of manufacturing the same.
2. Description of Related Art
The principles of operating a TFT are similar to those of operating a conventional metallic-oxide-semiconductor (MOS) transistor. Both the TFT and the MOS transistor have three terminals (a gate, a drain and a source). Each TFT functions as a switching element inside a liquid crystal display (LCD) pixel unit.
Currently, an organic thin film transistor (OTFT) has been developed in the industry. In comparison with the conventional TFT, the OTFT has advantages of lower processing temperature and lower manufacturing costs. Moreover, the OTFT can be applied to an active driving display, an IC card or other economical electronic products when the OTFT technology is adopted to plastic substrates.
U.S. Publication No. 2005/0242342 titled “ORGANIC THIN FILM TRANSISTOR INCLUDING ORGANIC ACCEPTOR FILM” and U.S. Publication No. 2006/0027805 titled “THIN FILM TRANSISTOR AND METHOD OF FABRICATING THE SAME” both disclose the OTFT-related technologies. The manufacturing process provided by the two U.S. publications is performed not only by a physical vapor deposition (PVD) and a chemical vapor deposition (CVD), but also by a vacuum deposition and photolithography. Thereby, the manufacturing costs are increased, and the acid or base solution does harm to material layers such as the organic semiconductor layers during the photolithography process.
On the other hand, the OTFT-related technologies are also disclosed in the non-patent reference titled “Enabling Gate Dielectric Design for All Solution-Processed, High-Performance, Flexible Organic Thin-Film Transistors” by J. Am. Chem. Soc. 2006, 128, p4554-4555. The technical feature thereof mainly lies in that a gold nano-particle layer is formed on an adhesive layer of a gate insulator as a source and a drain through a transfer printing method. However, adhesion among the material layers disclosed in the reference is undesirable due to the hydrophobic properties thereof. Furthermore, a mixing reaction frequently occurs among each of the material layers, which adversely affects the performance of the devices.
Hence, a method for manufacturing the OTFT with lower manufacturing costs and better performance has become an essential topic in the industry.